The present invention relates generally to an improved conveyor assembly for use in the thermal treatment of certain articles, and particularly for the continuous freezing of food articles, and more particularly to a support means for such a conveyor wherein the generally horizontally disposed support arms are designed to be as compact as possible in their thickness or height dimension so as to provide a maximum free-space or inter-flight dimensional opening or spacing. In this fashion, the design provides for an endless spirally-arranged conveyor track traveling about a predetermined path, the arrangement being such that the conveyor establishes a support platform or base with multiple flights or turns, tightly arranged about an axially ascending or descending path within the annular freezing zone. The endless conveyor track is supported on a plurality of axially and radially spaced apart unitary support arms, and thereby guide the conveyor along its predetermined spiral path or course.
In the past, upright spiral conveyors have been utilized for handling articles being subjected to thermally modifying environments, such as extremely low temperatures for the purposes of rapidly freezing food packages. These systems have been used for providing the chilling or even cryogenic environment for rapid freezing of food packages destined for use in either commercial markets, consumer markets, or both markets. The methods or techniques involved include exposure of the individual packages to extremely low temperatures, and with the time of exposure being a function of the temperature maintained within the freezing zone and the thermal treatment desired. The individual articles will have a dwell time which is dependent upon the temperature of the freezing zone and the characteristics of the articles being frozen. The efficiency of the system will be determined, to a great extent, upon the packing or stacking density of the articles within the system, with the space or volume efficiency being directly proportional to the packing or stacking density. Also, the external surface of the apparatus will determine operational efficiency, with thermal losses being, of course, influenced by the external surface required for the system. Thus, as the packing or stacking density is increased, the overall efficiency will be increased as well, since the other parameters of the apparatus are generally fixed and/or constant. The specific design feature or operational parameter which is improved and enhanced by the design of the present invention is the design of the support arms being employed to create and/or define the path of travel for the conveyor track within the annular thermal treating or freezing zone.